The discovery of fire was indisputably game-changing for the human species, how that discovery was made however has been long disputed; was the connection made accidentally with an inadvertent spark or through observation? A recently published study proposes it was the latter, that humans recognized the benefit of fire and knowingly worked to harness it.
The team from the University of Utah, led by Christopher Parker, a researcher with the University’s Anthropology department, have presented a new scenario proposing that early humans initially became reliant on fire as a result of the increasingly fire-prone environment present in Africa around two to three million years ago.
As conditions became drier, fueling an increase in naturally-occurring fires, our ancient ancestors would have recognized the advantage of scorched ground in their search for food. The authors of the study propose it was this altered landscape and the benefits that came along with it which encouraged early humans to become active arsonists.
Models developed using the Optimal Foraging Theory (OFT) allowed the team to speculate about the kind of benefits a fire-altered landscape would have given early humans. They concluded that with the increased energy and resources gained by using fire our ancestors were able to travel much farther, probably helping them migrate to other places.
OFT modeling helps predict how animals behave when they search for food. Acquiring food is what gives the animal energy, but finding and then capturing that food requires both time and energy. In order to maximize health and fitness, the animal will look for ways to gain the biggest benefit (in this case energy) for the lowest cost. OFT modeling helps in predicting the best strategy available to the animal to optimize the benefits.
The study is in direct contrast to other proposed scenarios, including the one suggesting the first fire resulted from a spark produced by rocks being pounded together, somehow lighting nearby shrubbery on fire. According to anthropology professor Kristen Hawkes, from the University of Utah and the new study’s senior author, those scenarios come up short.
“The problem we’re trying to confront is that other hypotheses are unsatisfying. Fire use is so crucial to our biology, it seems unlikely that it wasn’t taken advantage of by our ancestors,” she explained to Red Orbit, a University of Utah publication, “All humans are fire-dependent. The data show that other animals and even some of our primate cousins use it as an opportunity to eat better; they are essentially taking advantage of landscape fires to forage more efficiently.”
Her team’s scenario is the first one to suggest the use of fire was more than just happenstance and that early humans were forced to adapt to their ever more fire-prone environment. Once the tropical vegetation and climate was reconstructed, mimicking what existed in Africa approximately two to three million years ago, they discovered the evidence which led them to this new scenario.
Previous carbon analyses of soil from this time period (in Kenya and Ethiopia) indicates that between 3.6 million and 1.4 million years ago woody plants were starting to give way to the more tropical and fire-prone grasses. This, combined with reduced levels of carbon dioxide in the atmosphere and drier conditions caused the number of naturally-occurring fires to increase. In turn, this trend led our early ancestors to advantageously adapt to eating grassland plants and other foods cooked by these fires.
Eventually, early humans started to understand the benefits of fire, like how it reduced the time spent looking for food by exposing previously hidden animal tracks. Additionally, it stands to reason that they would learn that cooked foods were easier to eat and digest.
The study has been published in the journal Evolutionary Anthropology